C2 verb /ˈwɔːbəl/
warble
用颤抖的声音或发出颤音唱歌或吹口哨
Meaning
To sing or whistle with a quavering voice or with trills.
Example
The bird warbled a sweet tune in the morning.
那只鸟在早上用甜美的旋律歌唱。